Windows XP add/remove program problems

Last week I came across an interesting problem. I went to uninstall a program from a clients computer that I thought was causing some errors. Actually I know it was causing the errors because Event Log told me so, although I shouldn't put that much trust in Event Viewer but it does provide good answers sometimes. The problem was with Etrust Anti-spam and a corrupted install of Outlook. The whole Etrust package comes with a Anti-virus scanner, Anti-spam, Pest Patrol and a Firewall.

So the first step I tried was repairing the installation. With a big fat failure during repair I turned to uninstalling the application and try re-installing it. This is where my problem lay. Using the normal route of add/remove programs it uninstalled everything but the cause of the problem the Anti-spam software.

My next step was to traverse the registry and find the entry for uninstaller and all other entries for the software. Before doing this make sure you back up your registry to a folder on C:\
So I opened regedt32 and navigated to

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
Then I located the folder for Etrust and removed it. I also did a find for all references to Etrust and the Anti-spam software. Then I deleted the directory under Program Files.

That was basically it except for the re-install. Low and behold it worked just fine after that.
If you ever need to remove a program from add\remove programs that still shows up after you uninstall a program just visit the registry location above and remove the entries. You can also find the Uninstall string in the folder containing the programs registry entry.